Apparatus for a fluidized ion exchange bed system

ABSTRACT

A novel apparatus for an ion exchange system is provided. The apparatus comprises a first column for housing a first fluidized bed through which particles are flowed countercurrently to an ion-containing fluid to yield ion-loaded particles, a second column through which the ion-loaded particles are flowed countercurrently to an eluent fluid to yield regenerated particles, and a transport section which transfers the regenerated particles for re-introduction into the first column to repeat the ion exchange cycle in a continuous manner. A continuous method of ion exchange is also provided.

FIELD OF THE INVENTION

The present invention relates to an apparatus and ion exchange system,and more specifically, to a system comprising a liquid-solid circulatingfluidized bed arrangement.

BACKGROUND TO THE INVENTION

Fluidized beds have been used for a number of different applicationssuch as gas-liquid, gas-liquid-solid contactors and to carry out avariety of different processes including chemical reactions such as ionexchange.

Fluidized beds have found application in ion exchange processes. Forexample Chase, H. A., “Purification of Proteins by AdsorptionChromatography in Expended Beds”, TIBTECH 12, 296-303 (1994) describes abatch ion exchange process using a conventional fluidized bed forrecovering proteins from whole fermentation broth with the presence ofbacterial cells. It eliminates the difficult solids separation step andrecovers the desired products directly from unclarified whole broth.This process is a batch process employing a conventional fluidized bed.

Burns, M. A. and D. J. Graves, “Continuous Affinity Chromatography Usinga Magnetically Stabilized Fluidized Bed”, Biotechnology Progress 1,95-103 (1995) suggested a two-column magnetically stabilized fluidizedbed system for the continuous chromatography of biochemical products.The magnetically stabilized fluidized bed system is considered to becomplicated and costly.

Gordon, N. F., H. Tsujimura and C. L. Cooney, “Optimization andSimulation of Continuous Affinity Recycle Extraction”, Bioseparation 1,9-12 (1990) describes a process using mixed reactors as opposed to afluidized bed and reported the continuous affinity recycle extraction ofproteins using well-mixed reactors. This system, although simple andeasy to control, has the disadvantage of a stirred tank system—the ionexchange efficiency is low and large processing volumes are essentialfor even a moderate throughput requirement.

Further, various forms of apparatus have been described for use in suchchemical processes.

Porter and Robert, U.S. Pat. No. 3,879,287, “Continuous ion exchangeprocess and apparatus” (1975) relates to an apparatus for continuous ionexchange. However, the process described is a semi-continuous process asthe recommended eluting means is a batch wise conventional fixed bed ionexchange process.

Himsley and Alexander, U.S. Pat. No. 4,279,755: Continuouscountercurrent ion exchange process (1993) teaches a continuouscountercurrent ion exchange process for adsorbing ions of interest ontoion exchange particles from a feed liquor containing ions which whenadsorbed on the particles cause the density of the particles toincrease. The process comprises the steps of (1) flowing the feed liquorupwardly through a main bed of ion exchange resin particles contained ina main chamber of an absorption column and thereby maintaining the bedin fluidized state; (2) continuously collecting the denser loadedparticles from the lower region of the absorption column; (3) passing anoutflow of the feed liquor from the upper region of the main chamberupwardly into the lower region of the polishing chamber containing asecondary bed of fluidized ion exchange resin particles whereby residualions of interest are polished from the liquor, and (4) producing abarren liquor flowing out of the upper region of the polishing chamber.While this process offers continuous flow of feed liquor to the system,the movement, stripping and regeneration of the loaded ion exchangeparticles device is done on an intermittent basis.

Bassi et al., U.S. Pat. No. 6,716,344 describes a liquid solidcontinuous fluidized bed (LSCFB) comprising a conventional fluidized bedfor adsorption of ions and a riser co-current fluidized bed fordesorption of ions and regeneration of ion exchange particles. Ionexchange particles circulate continuously between the fluidized beds.The LSCFB is useful for continuous recovery of ions of interest,however, the nature of the design results in low particle regenerationefficiency, it consumes unfeasibly large quantities of fluids, and inmost applications, it results in significant dilution of processstreams.

SUMMARY OF THE INVENTION

An improved apparatus and circulating fluidized bed system forcontinuous, counter-current liquid-solids contact and interaction hasbeen developed and is referred to herein as a Vertically ArrangedLiquid-Solids Circulating Fluidized Bed (VA-LSCFB) ion exchanger.

In a first aspect, the present invention relates to an apparatus for afluidized bed system comprising:

a first column for housing a first fluidized bed, said first columncomprising a first particle-feeding means to feed ion exchange oradsorbent particles into an upper region of said first column and afirst fluid-feeding means to feed a first ion-containing fluid into alower region of said first column to form a fluidized bed in the firstcolumn, said first column further comprising a first fluid outlet in theupper region at a height above the first particle-feeding means, saidlower region being remote from said upper region such that said solidsand said fluid flow counter-currently in the first fluidized bed,wherein the upper region comprises a first end of the first column andthe lower region comprises a second end of the first column;

a second column for housing a second fluidized bed, a secondparticle-feeding means to feed particles into an upper end of saidsecond column and a second fluid-feeding means to feed a secondion-eluting fluid into a lower end of said second column to form asecond fluidized bed in the second column, a fluid outlet at the upperend of the second column at a height above the second particle-feedingmeans, said upper and lower ends being remote such that said particlesand said fluid flow counter-currently through said second column;

a first means connecting the first and second columns such that thesecond end of said first column is connected to the upper end of saidsecond column, said first connecting means being adapted to permitpassage of particles and prevent passage of said first fluid into saidsecond column;

a second means connecting the lower end of said second column to atransport section, said second connecting means being adapted to permitpassage of particles and prevent passage of said second fluid; and

a transport section which connects to the upper region of the firstcolumn, said transport section comprising means to hydraulically movesaid particles upwardly into a liquid-solids separator to separate theparticles from fluid prior to entry into the first column via the firstparticle-feeding means.

Preferably said first and second columns are substantially verticalcolumns. The preferred arrangement of the first and second columns issuch that the first column is situated at a height above at least aportion of the second column, and preferably, is situated at a heightabove a large portion of the second column. In one preferred embodiment,the lower region of the first column is substantially adjacent to theupper end of the second column.

Preferably said first column comprises an ion exchange or adsorbentparticle bed for separating ions of interest and said second columncomprises a fluidized bed that functions to regenerate ion-loadedparticles by elution of ions of interest.

Preferably, the first means connecting the first and second columns issubstantially adjacent to the second end of the first column and theupper end of the second column.

Optionally the first means connecting said first and said second columnsincludes a washer for washing ion exchange or adsorbent particles whichis adjacent to the second end of said first column before they areintroduced into the second column.

Optionally, in cases where elution of ions of interest requires highlevels of ionic driving force, the second column may comprise multiplefluid-feeding inlets, preferably arranged in series, separated from eachother along the column for introduction into the system of the elutingfluid.

Optionally the second connecting means comprises a washer to washparticles from the second column before they are introduced into thetransport section. The washer may be located adjacent to the lower endof the second column.

Optionally said means to hydraulically move particles from the transportsection to the upper region of said column comprises one or more fluidinlets for injection of transport fluid into the transport section, andoptionally comprises an inlet for compressed gas. The fluid inlet maycomprise primary and auxiliary inlets.

In a case in which a high quality product is required, the separator mayinclude an inlet at the bottom of the separator for the introduction ofa blocking fluid into the separator, the function of which is to preventtransport fluid from being carried into the first column by theparticles or to otherwise prepare the particles for entry/re-entry intothe first column (e.g. such as pH conditioning of the particles).

In another aspect of the invention, a continuous method for recoveringions of interest from a fluid is provided. The method comprises thesteps of:

i) passing ion exchange or adsorbent particles in a downward flowcountercurrent to the flow of the fluid to yield ion-loaded particles;

ii) removing the fluid from said ion-loaded particles;

iii) passing said ion-loaded particles in a downward flow countercurrentto an eluting fluid for desorption of said ions of interest from saidparticles to provide regenerated particles;

iv) removing the eluting fluid containing the desorbed ions of interestfrom said regenerated particles; and

iv) transporting said regenerated particles for use to repeat stepsi)-iv) in a continuous manner.

The present system and method advantageously provide continuouscountercurrent separation of ions of interest and uninterruptedregeneration and circulation of solid particles through the system.

Further features and advantages will be evident from the followingdetailed description of the preferred embodiments of the presentinvention taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic illustration of an apparatus in accordance with anembodiment of the present invention;

FIG. 2 graphically illustrates the conductivity when NaCl is introducedinto the system at the feed inlet;

FIG. 3 graphically illustrates the conductivity when NaCl is introducedinto the system at the eluent inlet;

FIG. 4 graphically illustrates the conductivity when NaCl is introducedinto the system at the desorber wash inlet;

FIG. 5 graphically illustrates the conductivity when NaCl is introducedinto the system at the transport fluid inlet;

FIG. 6 graphically illustrates the conductivity when NaCl is introducedinto the system at the separator block inlet;

FIG. 7 graphically illustrates the conductivity when NaCl is introducedinto the system at the adsorber wash inlet; and

FIG. 8 graphically compares conductivities at all system outlets duringsteady-state operation during demineralization of a sugar solution.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1, an embodiment of the present invention is shown. Anapparatus 100 useful for ion exchange comprises a first column 10 and asecond column 12 interconnected generally by solid transfer and washingsystems as will be described. First and second fluidized beds are formedin the first and second columns 10, 12, respectively, when ion exchangeor adsorbent solid particles 18 are input into each column along withfluids, such as feed liquor and eluting fluids.

The first column 10 comprises a first particle-feeding transfer line 17by which solid particles 18 are input into the upper region of the firstcolumn 10 (e.g. within the region above the midpoint of the first column10) via inlet 73 for downward flow within the first column 10. The firstcolumn 10 also comprises a fluid-feeding inlet 22 to feed a firstfluidizing fluid, e.g. a feed liquor 20, into the lower region 24 forupward flow in the first column 10 (e.g. within the region below themidpoint of column 10). The particles 18 and feed liquor 20 flowcounter-currently through the first column 10. The feed liquor isremoved from the first column 10 via outlet 60 located at the top of thefirst column 10.

A first washer 34 is optionally connected to the bottom end 35 of thefirst column 10. The washer 34 may be any region or section suitable towash ion-loaded particles, for example, a short column, Wash fluid froma source 36 is injected into the washer 34 via first wash (adsorber)inlet 38 positioned at the bottom of the washer 34. The injected washfluid is flowed counter-current to the particles 18 by the selection ofappropriate inlet and outlet flow rates and equipment configuration.Excess fluid, such as feed liquor 20, is removed from the washer 34through a screened outlet 32. The screen size is selected based on thesize of solid particles being used in the apparatus 100 such thatparticles are retained within the washer 34 while excess fluid isremoved.

The primary function of the optional first washer 34 is to prevent thefeed liquor 20 from being carried into the second fluidized bed 12 bythe particles 18. The washer 34, thus, is included when the conditionsof the specific application of the system call for this level ofseparation. The optional washer 34 may also be used to scour or cleansolid particles in those cases where the feed liquor 20 (firstfluidizing fluid) contains compounds that cause substantial resinfouling such as silicates, organics, bacterial or other compounds.

A first connecting means, e.g. transfer line 14, extends from the bottomof the first column 10 (or from the bottom of washer 34, if present) andconnects the first column 10 to the upper end of the second column 12including inlet 74 (second particle-feeding means). Inlet 74 is locatedat a point above the mid-region of the second column 12. The firsttransfer line 14 is adapted to permit passage of particles 18 and toprevent passage of fluid, e.g. feed liquor, from the first column 10into the second column 12. In one embodiment, the first transfer line 14operates as a packed moving bed and is configured to comprise a firstdynamic seal between the second fluidized bed in the second column 12and the first fluidized bed in the first column 10. For the purposes ofthe present system, the term “dynamic seal” is used herein to refer toan arrangement to prevent the passage of one gas or liquid into a secondliquid through the control of pressures and mixing at the gas/liquidand/or liquid/liquid interface. The dynamic seal is used to achieveseparation of liquids from the first and second fluidized beds (e.g. toprevent the feed liquor 20 from the first fluidized bed from enteringthe second fluidized bed), as well as to adjust and control the solidscirculation rate and system productivity. In the VA-LSCFB ion exchangesystem of the present invention, the first transfer line 14 comprises avalve 70 for use to control, in part, the first dynamic seal.

A second fluidizing fluid (eluent) is introduced into the lower end ofthe second column 12 through one or more second fluid-feeding inlets 26and is flowed counter-currently to particles 18 entering the secondcolumn 12 through inlet 74. The particles 18 are regenerated by thecounter-current exposure to the eluent, e.g. the adsorbed ions ofinterested are desorbed from particles 18 by the eluent. In cases whereelution of the ions of interest requires a high level of ionic drivingforce, the second column 12 may include multiple inlets 26, preferablyarranged in series, separated from each other in the lower end of thesecond column 12 for introduction of eluting fluid into the system inorder to effectively drive ion removal, concentrate eluent, and achieveparticle regeneration.

Excess eluent is removed from the second column 12 through a screenedoutlet 63 at the top of the second column 12. The outlet 63 is locatedabove inlet 74 such that a freeboard section of sufficient height isestablished between the outlet 63 and inlet 74 to substantiallyeliminate carryover of particles 18 through the outlet 63. The screensize of the outlet 63 is selected based on the size of solid particles18 being used such that particles 18 are retained within the systemwhile excess eluent is removed.

A second optional washer 30 extends from the bottom end 29 of the secondcolumn 12 and may also be any suitable region or section for washing theparticles. Wash fluid from a source 37 is injected into the washer 30via second wash (desorber) inlet 33 which is located at the bottom ofthe second washer 30. Excess wash fluid is removed from the secondwasher 30 through a screened outlet 31 which comprises a screen sizeselected to retain the solid particles 18 being used in the systemwithin the washer 30.

A second connecting means, e.g. second transfer pipe 15, connecting thesecond column 12 to a transport section 50, extends from the bottom ofwasher 30 (or from the bottom of the second column 12 if a second washeris not present) to the transport section 50. The second transfer pipe 15is adapted to permit passage of particles 18 and prevent passage offluid, e.g. eluent. In one embodiment, the second transfer pipe 15comprises a second dynamic seal between the second fluidized bed in thesecond column 12 and the transport section 50. In the system of thepresent invention, the second transfer pipe 15 comprises a valve 72 foruse to control, in part, the second dynamic seal. Transfer pipe 15 feedsparticles into the transport section 50 via inlet 75.

The transport section 50 comprises a riser 16 which permits transport ofparticles for entry back into the first column 10. Transport fluid isinjected from source 54 into the transport section 50 via inlet 52 tohydraulically transfer particles 18 upwardly through riser 16. Thetransport fluid inlet 52 optionally consists of two inlets, a primaryinlet and an auxiliary inlet. The primary inlet may be a nozzle whichprojects into the riser section 16, and the auxiliary inlet may be aperforated plate at the bottom of the transport section 50 which is usedto stir up the particles entering the bottom of the transport section50. A compressed gas such as air or nitrogen may optionally beintroduced into the transport section 50 via inlet 55 to aid with thehydraulic transport of particles 18.

The riser 16 connects to a liquid-solids separator 46, such as a vortextype separator, at inlet 57. Separator 46 functions to separate theparticles 18 from transport fluid prior to entry into the first column.The separator 46 comprises at its upper end, a fluid outlet 65 forremoval of separated transport fluid, and at its lower end, an outlet 47for solid particles. Inlet 57 is sufficiently below the outlet 65 tomaintain a freeboard section in the upper region of the separator 46 ofsufficient height to substantially eliminate carryover of particles 18through the outlet 65. The separator 46 optionally includes an inlet 56for injection of a blocking fluid, such as water, buffer or excess feedliquor, from a source 58. The function of the blocking fluid is toprevent transport fluid from being carried into the first column by theparticles or to otherwise prepare the particles for entry into the firstcolumn (e.g. pH conditioning of the particles). A third connectionmeans, e.g. transfer pipe 17, connects outlet 47 of the separator 46 tothe first column 10 and functions to deliver regenerated particles 18into the top of first fluidized bed within first column 10 via inlet 73.Inlet 73 is located sufficiently below outlet 60 to maintain a freeboardsection in the upper region of the first column 10 of sufficient heightto substantially eliminate carryover of particles 18 through the outlet60. The third transfer pipe 17 may be adapted to prevent passage oftransport fluid into the first column while permitting passage ofregenerated particles. In one embodiment, the third transfer pipe 17comprises a third dynamic seal between the separator 46 and the firstcolumn 10. In this embodiment, the third transfer pipe 17 may comprise avalve 71 for use to control, in part, the third dynamic seal.

The first column 10 or the second column 12 may include the addition ofinternal elements within the column such as baffles, mixers, contactors,or distributors of varying design, if necessary, for the purpose ofcontrolling liquid-particle contact within the column, as may be thecase, for example, under conditions of slow exchange kinetics.

The operation of the invention will be described below in relation tothe ion exchange process; however, as one of skill in the art willappreciate, it may be used in other potential applications.

In the process of ion exchange, a first fluidized bed is formed in thefirst column 10 of ion exchange apparatus 100 by introducing ionexchange particles 18 into the upper region of the first column 10 viatransfer pipe 17 and a feed liquor 20 into the lower region 24 of thefirst column 10 via inlet 22, i.e. the feed liquor 20 and particles 18are introduced at opposite ends of the first column 10. Particles 18 areselected to be appropriate to bind target ions in the feed liquor 20 forremoval of such ions from the feed liquor.

The first fluidized bed is sized based on the characteristics of theion-containing fluid, such as the concentration of ions of interest orthe presence of competing ions; the characteristics of the ions ofinterest, such as their selectivity; and the characteristics of the ionexchange particles, such as their particle exchange capacity. Generally,the first fluidized bed is sized to achieve an appropriate ratio ofparticles to fluid, and an appropriate liquid residence time andparticle residence time in order to capture the desired level of ions ofinterest, resulting in either complete or partial removal. As one ofskill in the art will appreciate, bed sizing can vary widely dependingon the application of the apparatus, for example, the bed may be lessthan 0.5 cubic meter for an application with a low feed ionconcentration, or 10 cubic meters or higher for an application with ahigh feed ion concentration.

The falling particles 18 and the up-flowing feed liquor 20 contactcounter-currently and target ions in the feed liquor 20 are bound by theion exchange particles 18 in the first fluidized bed. The deionizedliquor is removed from the system at the top of the first column 10through outlet 60 for downstream processing, use, or discard. Theion-loaded particles 18 fall into the optional washer 34 at the base ofthe first column 10. Wash fluid injected into washer 34 via inlet 38 isflowed counter-current to the particles 18 by the selection ofappropriate inlet and outlet flow rates and equipment configuration, andare then transferred via first transfer pipe 14 to the upper end of thesecond column 12. The first transfer pipe 14 located between the secondcolumn 12 and the first column 10, which may operate as a packed movingbed comprising a first dynamic seal, prevents the entry of feed liquor20 into the second column 12.

The second fluidizing eluent, selected to remove the target ions boundto the particles 18, is injected into the lower end of the second column12 through inlet(s) 26 and is flowed in an upward directioncounter-currently to the downward flow of loaded ion exchange particles18 to form a second fluidized bed within the second column 12. Thisresults in removal of target ions from particles 18 and regeneration ofthe particles 18. The ion-containing eluent is removed from the secondcolumn 12 through outlet 63 and may be subjected to further downstreamprocessing, use, or discard. The regenerated ion exchange particles 18are optionally washed in second washer 30. The wash fluid injected intowasher 30 via inlet 33 is flowed counter-current to the particles 18 bythe selection of appropriate inlet and outlet flow rates and equipmentconfiguration. The washed particles 18 are transported through thesecond transfer pipe 15 which may operate as a packed moving bedcomprising a second dynamic seal to permit the entry of regeneratedparticles and prevent the passage of eluent into the transport section50.

The second fluidized bed is sized based on the characteristics of theeluent, such as concentration; the characteristics of the ions ofinterest, such as the ionic charge; and the characteristics of the ionexchange particles, such as the particle exchange capacity, to achievean appropriate ratio of particles to fluid, liquid residence time andparticle residence time, in order to accomplish the desired level ofparticle regeneration.

The regenerated particles are then hydraulically transported upwardly byinjection of transport fluid into the transport section 50 via inlet 52,optionally assisted by injection of gases via inlet 55, through riser 16to liquid-solids separator 46. The liquid-solids separator 46 functionsto separate the regenerated particles 18 from the transport fluid. Theseparator may be any type of separator such as a vortex or hydrauliccyclone separator. Separated fluid, such as transport fluid, iseliminated through separator outlet 65 located in the upper end of theseparator at a level appropriately relative to that of the outlet 60 inthe upper region of the first column 10 to maintain the appropriatepressure balance within the system. To prevent the loss of particles 18through the separator outlet 65, a stainless steel mesh (not shown) ispreferably used to cover the separator outlet 65. Blocking fluid may beintroduced into the separator 46 via inlet 56.

The regenerated particles 18 are introduced/re-introduced into the firstcolumn 10 through the third transfer pipe 17, which may comprise adynamic seal, via inlet 73. The regenerated particles 18 are floweddownwardly through the first fluidized bed countercurrently to upwardlyflowing feed liquor 20 to repeat the cycle of ion removal from the feedliquor and subsequent regeneration of particles through the VA-LSCFBsystem.

As one of skill in the art will appreciate, the rate of circulation ofthe particles, and the flow rates of fluids within the system, will varydepending on the feed and product characteristics.

In certain circumstances, based on the characteristics of theion-containing fluid, ions of interest or eluting fluid, or based on theoperating conditions of the system such as the presence of solids orfoulants, the formation of by-products, or other process conditions, thefunction of the first and second columns of the apparatus may bereversed, such that the second column is used for the capture of ions ofinterest and the first column is used for the regeneration of particles.

The present VA-LSCFB system has many advantages. At the outset, thesystem provides a means to conduct continuous method of ion exchange inwhich ion exchange or adsorbent particles are introduced into the systemto remove target ions from a feed liquor, are regenerated continuouslyby ion removal and recirculated for reuse to remove target ions from thefeed liquor.

A major advantage of the VA-LSCFB system is realized in that theVA-LSCFB system separates elution of regenerated ion exchange particlesfrom the upward transport of these regenerated particles. By theprovision of a second fluidized bed that is not a riser fluidized bed,the regeneration of the particles is more efficient, significantlyreducing the consumption of chemicals (e.g. eluent) required forparticle regeneration. In addition, in the present VA-LSCFB, the secondfluidized bed operates as a counter-current bed, which provides a strongdriving force for elution of ions of interest, further reducing theconsumption of chemicals required for particle regeneration.

In addition, the second column of the VA-LSCFB may optionally beequipped with multiple eluent inlets arranged in series to concentrateeluent and strongly drive ion removal and particle regeneration withinthe second fluidized bed. This can be a particularly important featurein the case where a strong elution driving force is necessary to achieveion removal from particles, e.g. elution of proteins from strong baseanionic particles (resins).

A further advantage of the VA-LSCFB is provision of optional washingsections designed to minimize dilution of process streams throughout thesystem, thereby reducing downstream processing costs.

The VA-LSCFB is designed for use with most ion exchange or adsorbenttype resins including, but not limited to, cationic, anionic, weak,strong, gel-type, macroporous, dense core, or other similar solidparticles. The VA-LSCFB is thus suitable for use to remove manydifferent target ions from a wide variety of feed liquors or fluids.

Suitable feed liquors/fluids may contain one or more ions of interest.Examples of feed fluids include, but are not limited to, any source ortype of water, an in-process or finished product stream in food,beverage, nutritional, pharmaceutical, biofuel, agricultural,ingredient, or basic chemical processing, an organic solution, afermentation broth, mine water, industrial processing or ingredientwater, wastewater, and the like. Target ions of interest for removalfrom such feed liquors include, but are not limited to, metal ions,mineral ions, organic acids, color bodies, proteins, amino acids,enzymes, phenolics, salts, alcohols, or other ionic compounds orcontaminants.

Suitable eluent fluids generally include eluents, buffered orunbuffered, suitable for target ion removal and regeneration of thesolid ion exchange particles selected for use in the system. Examples ofsuitable eluents include, but are not limited to, acids such as HCl andH₂SO₄, bases such as NaOH, salts such as NaCl or KI, or other ionicsolutions.

Having described the invention, modifications will be evident to thoseskilled in the art without departing from the spirit of the invention asdefined in the appended claims.

Embodiments of the invention are described by way of the followingspecific example which is not to be construed as limiting.

Example 1 Conductivity Profiling of a VA-LSCFB Ion Exchanger with NaCl

The use of a VA-LSCFB ion exchanger in accordance with an embodiment isdescribed. The VA-LSCFB ion exchanger is as generally shown in FIG. 1.Although the particulars may vary, the particulars of the exchanger usedin this example are as follows. The first column comprised a glasscolumn of I.D. 4.4 cm and 91 cm in height. The feed inlet was astandpipe with four outlets evenly distributed into the column diameter,and located 16 cm from the bottom of the column. The solid particleinlet was located 51 cm from the top of the column.

The first optional washer was a glass bulb 8 cm in height and 3.5 cm indiameter, connected to the bottom of the first column through a funnel1.25 cm in diameter and 1.5 cm in height. The wash inlet was a standpipewith four inlets evenly distributed into the washer diameter. Twooutlets were located in close proximity to the funnel at the top of thewasher. The bottom of the washer was connected to the top of the secondcolumn using 2 cm I.D. tubing, 14 cm in length.

The second column comprised a glass column 3 cm in diameter, and 33 cmin height. The inlet to the second column was a standpipe with fourinlets evenly distributed into the second column diameter withapproximately 14 cm from the bottom of the column. An outlet from thesecond column was located at the top of the bed.

The optional second washer was 3.5 cm in diameter and 11 cm in heightintegrated directly with the bottom of the second column. Wash fluidentered into the washer through a standpipe 3.5 cm high, located in thebottom of the washer. The bottom of the washer was connected to thetransport section using 1 cm I.D. tubing, 20 cm in length.

The transport section comprised a glass inlet section 5 cm high intowhich transport fluid entered through a standpipe 4 cm high. An optionalcompressed air inlet was located at the top of the inlet section. Thetop of the inlet section was connected to a 1 cm diameter riser tubing,164 cm long, which was connected to the liquid-solid separator 18 cmfrom the top.

The liquid-solid separator was 3.8 cm in diameter and 47 cm high. Theeffluent outlet was located 10 cm from the top of the separator,allowing sufficient height from the inlet tubing from the second washerto allow for creation of a free-board section with no solid particles.The bottom of the liquid-solid separator included an optional inlet forthe introduction of blocking fluid as described, and was connected tothe solid particle inlet of the first column using tubing 1.5 cm I.D.and 30 cm in length.

Conductivity is the measurement commonly used to demonstrate theoperation of an ion exchange system. The above system was used withsolutions of NaCl to conduct system conductivity profiling thatdemonstrates the achievement and maintenance of the necessary fluiddynamics, dynamic seals, movement and separation of fluids and resins.For this demonstration, fresh Lewatit MP 600 strong-base Type IImacroporous anionic resin was used. Once the system was brought intosteady state operation using known techniques, NaCl solution wasintroduced first through the feed inlet 22 and conductivity of allsystem outlets was measured for a period of 120 minutes. The NaCl wasflushed from the system, and then introduced through the eluent inlet 26and conductivity of all system outlets was measured for a period of 120minutes. The same procedure was used for the introduction of NaClthrough wash liquid inlet(s) 38/33, transport fluid inlet 52 andblocking fluid inlet 56. The following conditions were used:

TABLE 1 NaCl Solution Concentration - NaCl 0.25M Conductivity 29,000μS/cm Wash Water Tap Water pH 7.66 Conductivity 662 μS/cm Flow RatesFeed Flow Rate 80 mL/min Adsorber Wash Flow Rate 5-10 mL/min TransportFlow Rate 13 mL/min Separator Block Flow Rate 5 mL/min Eluent Flow Rate(per inlet, 4 inlets) 3 mL/min

As shown in FIGS. 2 through 7, a comparison of conductivities from allsystem outlets during the introduction of NaCl into one inletdemonstrates the achievement of liquid and solid movement andseparation. For example, FIG. 2 shows that NaCl introduced through thefeed inlet can be detected primarily in the adsorber outlet and adsorberwash outlet as expected, and has minimal affect on the conductivity ofthe regenerator outlet or the separator outlet. FIG. 3 shows that NaClintroduced through the eluent inlets can be detected primarily in theregenerator outlet, but has minimal effect on the other outlets, asexpected. Similarly, FIGS. 4 through 7 show the expected results forintroduction of NaCl through the desorber wash inlet, transport fluidinlet, separator block inlet, and adsorber wash inlet, respectively. Theresults of this conductivity profiling clearly demonstrate that theVA-LSCFB achieves and maintains the separation and movement of liquidsand solids as required.

Example 2 The Use of a VA-LSCFB Ion Exchanger with Sucrose as a FeedLiquor

Conductivity profiling was also conducted with a 20% sucrose solutionusing Lewatit MP 600 strong-base Type II macroporous anionic resin. Oncethe system was brought into steady state operation, the conductivity ofall system outlets was measured for a period of 120 minutes. Thefollowing conditions were used:

TABLE 2 Feed Solution Concentration - Sucrose 20% Temperature 30° C. pH7.78 Conductivity 56.5 μS/cm Flow Rate 75 mL/min Wash Water DistilledWater pH 7.66 Conductivity 21.5 μS/cm Adsorber Wash Flow Rate 5 mL/minTransport Flow Rate 13 mL/min Separator Block Flow Rate 5 mL/min EluentConcentration - NaOH 1M pH 13.51  Conductivity 191,000 μS/cm Flow Rate(per inlet, 4 inlets) 3 mL/min

As shown in FIG. 8, a comparison of conductivities from all systemoutlets during steady-state operation with a sucrose solutiondemonstrates the achievement of liquid and solid movement andseparation,

Example 3 Nickel Removal Using Cationic Ion Exchange

Using an apparatus and conditions similar to that described in Example 1and 2, Lewatit 2568 strong-acid macroporous cationic resin was used toremove the target ion calcium (from CaCl₂.2H₂O) from an aqueoussolution. After 80 minutes conditioning, the system was run for 110minutes at an average calcium removal efficiency of 98.7%, and aconductivity profile demonstrating the achievement of liquid and solidmovement and separation.

What is claimed is:
 1. An apparatus for a fluidized ion exchange bedsystem comprising: a first column for housing a first fluidized bed,said first column comprising a first particle-feeding inlet to feed ionexchange or adsorbent particles into an upper region of said firstcolumn and a first fluid-feeding inlet to feed a first ion-containingfluid into a lower region of said first column to form a fluidized bedin the first column, said first column further comprising a first fluidoutlet in the upper region at a height above the first particle-feedingmeans, said lower region being remote from said upper region such thatsaid particles and said fluid flow counter-currently in the firstfluidized bed, wherein the upper region comprises a first end of thefirst column and the lower region comprises a second end of the firstcolumn; a second column for housing a second fluidized bed, said secondcolumn comprising a second particle-feeding inlet to feed particles intoan upper end of said second column and a second fluid-feeding inlet tofeed a second ion-eluting fluid into a lower end of said second columnto form a second fluidized bed in the second column, said second columnfurther comprising a second fluid outlet at the upper end of the secondcolumn at a height above the second particle-feeding means, said upperand lower ends being remote such that said particles and said fluid flowcounter-currently through said second column; a first conduit whichconnects the first and second fluidized beds such that the second end ofsaid first column is connected to the upper end of said second column,said first connecting conduit being adapted to permit passage ofparticles and prevent passage of said first ion-containing fluid intosaid second column; a second conduit which connects the lower end ofsaid second column to a transport section, said second connectingconduit being adapted to permit passage of particles and prevent passageof said second ion-eluting fluid, wherein said transport sectionconnects to the upper region of the first column via a liquid-solidsseparator and permits hydraulic transport of said particles upwardlyinto the liquid-solids separator to separate the particles from fluidprior to entry into the first column via the first particle-feedinginlet.
 2. The apparatus as defined in claim 1, wherein the first andsecond columns comprise ion exchange or adsorbent particles to formfirst and second fluidized beds.
 3. The apparatus as defined in claim 2,wherein the particles are selected from the group consisting ofcationic, anionic, weak, strong, gel-type, macroporous and dense core.4. The apparatus as defined in claim 2, wherein the separator isconnected to the first column via a third connection conduit adapted topermit passage of particles and prevent passage of fluid into said firstcolumn, wherein the third connection conduit delivers particles into thefirst column through the first particle-feeding inlet.
 5. The apparatusas defined in claim 1, wherein the first column is situated at a heightabove at least a portion of the second column.
 6. The apparatus asdefined in claim 1, wherein the second end of the first column issubstantially adjacent to the upper end of the second column.
 7. Theapparatus as defined in claim 1, comprising multiple secondfluid-feeding inlets within the lower end of the second column.
 8. Theapparatus as defined in claim 1, wherein said first connecting conduitcomprises a washer to wash particles from the first column before theyare introduced into said second column.
 9. The apparatus as defined inclaim 1, wherein the second connecting conduit comprises a washer towash particles from the second column before they are introduced intothe transport section.
 10. The apparatus as defined in claim 1, whereinthe transport section comprises one or more fluid inlets and optionallycomprises an inlet for compressed gas.
 11. The apparatus as defined inclaim 1, wherein the fluid outlets comprise a screen to prevent exit ofsaid particles.